Implantable medical systems including implantable medical devices (IMD) and associated implantable medical leads provide functions such as stimulation of muscle or neurological tissue and/or sensing of physiological occurrences within the body of a patient. Typically, the IMD is installed in a subcutaneous location that is accommodating and relatively accessible for implantation. For instance, to provide stimulation near the spine or pelvis, the IMD may be installed in a pocket located on the abdomen or upper buttocks region of the patient. The implantable medical lead is installed either through a percutaneous procedure or a surgical procedure, depending upon the type of lead that is necessary.
For a percutaneous implantation procedure, the implantable medical lead is inserted via an introducer needle that provides a passageway for the lead to enter the body. The lead is fed through the introducer needle, and a distal end of the lead is steered along a desired path until reaching the stimulation site. To force the lead though the body to the stimulation site, a stylet is inserted into a lumen of the lead. One stylet may have a straight distal end to force the lead in a straight direction while another stylet may have a bent distal tip to urge the lead to turn in a particular direction.
The doctor implanting the lead may steer the lead by rotating a stylet hub on the proximal end of the stylet. The stylet is torsionally stiff so that rotating the stylet hub on the proximal end results in the bent tip on the distal end rotating as well. The doctor rotates the stylet hub until the distal tip has rotated to a position that will urge the lead in the desired direction. Insertion force is applied to the lead to move the lead in the desired direction. When a new direction is needed, the doctor reaches back to the end of the stylet to again rotate the stylet hub.
While steering the lead with the stylet hub is effective at rotating the distal tip of the stylet, it can be cumbersome for the doctor. The doctor works directly with the lead at the site of the introducer needle to apply an insertion force, but the remainder of the lead to be implanted, and hence the remainder of the stylet, may extend behind the doctor for a significant distance. Thus, the doctor may have to reach back to the proximal end of the lead to grasp the stylet hub each time a steering input is needed. Reaching back and forth between the lead at the introducer needle and the stylet hub can be time consuming and burdensome.